Fixes & improvements:
- Removed non-functional Auto-ANC toggle (firmware rejects autoCnc=1 with a runtime error; manual level control is unaffected)
- Switching Listening Mode now updates ANC level, Spatial Audio and Wind Block in ~400 ms instead of ~3 s
- Toggles (Spatial Audio, Wind Block, EQ, Sidetone, Multipoint, Auto Play/Pause, Auto Answer) no longer trigger a full device re-read — response is immediate
- Fixed: Bluetooth socket was leaked when the initial state fetch failed right after connecting
- Fixed: Listening Mode list no longer flickers/rebuilds on every 15 s background poll when modes haven't changed
- Removed dead code: ButtonConfig class and button-address constant (button remapping requires Bose cloud auth)
- Added app icon for F-Droid store listing
